Introduction

Overview and Motivation

During the last 2 years, COVID-19 has been a main focus of the news. Though around 3% of the world population had COVID-19, diabetes can be considered as an even bigger health problem. Indeed, according to the International Diabetes Foundations (IDF), in 2019, 463 million adults were living with diabetes (around 6-7% of the world population) and this number is forecasted to rise to 700 million by 2050. Furthermore, 90% of cases of diabetes are of type 2, which means it results mainly from bad habits and not genetics. However both types of diabetes can be treated and/or prevented with a healthier diet and more physical activity. Additionally, according to the WHO, low income countries are more susceptible to having higher diabetes prevalence. Living in Europe, we observed that diabetes rates differ a lot from one country to another, so we wanted to find out if these rates were indeed linked to a country’s income, and if the nutritious composition of richer states’ population’s diet is also affected by this income difference and if yes, how it is affected.

Research questions

Therefore, we would like to find out answers to the following questions :

  1. Do European countries that have higher GDPs really have lower diabetes prevalence ?

  2. Do European countries that have higher GDPs consume less calories ?

  3. How do the proportions of macronutrients (animal protein/plant protein/fat/carbohydrates) consumed differ between richer and poorer governments ?

  4. And how do these differences relate to the diabetes prevalence in these countries ?

  5. What is the typical diet that can be observed in richer states that relates to lower diabetes prevalence ?

Data

To answer our research questions, we used three different datasets. While searching for datasets, we made sure that the years and countries matched for every one of them.

Wrangling and cleaning

Caloric consumption

The first dataset we used, downloaded from the portal https://ourworldindata.org/diet-compositions, contains information related to the consumption of macronutrients in calories for different countries. It gives us information on the average nutrition of different countries from 1961 to 2013 :

  • It is composed of 8981 observations of 7 variables:

    • Entity Name of the country
    • Code ISO country code
    • YearYear of the observation
    • Calories from animal protein (FAO (2017)) The average per capita supply of calories derived from animal protein all measured in kilocalories per person per day
    • Calories from plant protein (FAO (2017)) The average per capita supply of calories derived from plant protein, all measured in kilocalories per person per day
    • Calories from fat (FAO (2017))The average per capita supply of calories derived from fat, all measured in kilocalories per person per day
    • Calories from carbohydrates (FAO (2017)) The average per capita supply of calories derived from carbohydrates, all measured in kilocalories per person per day

The intake of specific macronutrients (carbohydrates, protein and fats) are derived based on average food composition factors – these factors are derived and presented in the Food and Agriculture Organisation’s (FAO) Food Balance Sheet Handbook (https://www.fao.org/faostat/en/#data).

We will only focus on observations of European countries in the 2000s.

We used the ISO code as it is standardized worldwide and does not have the risk of having different names in different tables like the countries’ names.

Then, we proceeded to compute the mean of the consumption for each type of macronutrient in each country between the years 2000 and 2013, and the sum of total calories per person per day for each country in order to answer our second research question.

We then created a new table by adding the sum of total calories per person per day for each country in order to get a broader view with the total consumption of calories. To make sure that the joining of tables go smoothly, we also removed duplicates and the country name column.

Our assumption was that a county’s wealth may fluctuate over the course of 10 years (ex: a dip during the economic crisis of 2008) but an overall mean is sufficient to compare the different countries and their riches.

  • We now have a dataframe with the following variables :

    • country_code ISO country code
    • cal_prot_animalThe mean of the calories from animal protein consumed in each country in the years 2000-2013
    • cal_prot_plant The mean of the calories from plant protein consumed in each country in the years 2000-2013
    • cal_carbsThe mean of the calories from carbohydrates consumed in each country in the years 2000-2013
    • cal_fat The mean of the calories from fat consumed in each country in the years 2000-2013
    • total_consumption The total consumption based on the means of the consumption of each type of macronutrients in each countries in the years 2000-2013
The final table is the following:
Table 1: Caloric Consumption
Country Code Calories from animal protein Calories from plant protein Calories from carbohydrates Calories from fat Total consumption
AUT 245 169 1833 1454 3702
BEL 238 158 1856 1467 3719
BGR 155 168 1606 846 2775
HRV 168 148 1691 940 2946
CYP 197 127 1291 1019 2633
CZE 218 153 1728 1155 3254
DNK 273 157 1746 1190 3366
EST 212 167 1967 842 3188
FIN 269 166 1623 1177 3234
FRA 293 161 1611 1480 3545
DEU 240 159 1785 1276 3460
GRC 250 204 1744 1338 3536
HUN 193 153 1560 1221 3126
IRL 279 174 1950 1187 3590
ITA 241 204 1776 1390 3612
LVA 203 154 1687 1044 3087
LTU 274 198 2055 858 3385
LUX 288 148 1752 1318 3507
MLT 237 204 1932 994 3367
NLD 292 136 1599 1195 3222
POL 204 197 1969 1035 3405
PRT 275 177 1824 1240 3516
ROU 200 220 2003 916 3340
SVK 140 150 1610 952 2853
SVN 230 168 1664 1067 3129
ESP 279 159 1481 1323 3243
SWE 285 143 1566 1137 3131
CHE 237 138 1660 1392 3426
GBR 232 178 1748 1256 3414

GDP

Our second dataset, downloaded from the portal https://data.worldbank.org, gives us information about the GDP of many countries over the course of 60 years (1960-2020).

  • It is composed of 266 observations of 65 variables :

    • Country Name Name of the country
    • Country Code ISO country code
    • Indicator Name equal to “GDP in current US$” for every row
    • Indicator Code equal to “NY.GDP.MKTP.CD” for every row
    • And a variable for each year from 1960 to 2020

As we can see below, RStudio imported the Excel file as is, and so our column names found themselves at the 3rd row and therefore column names of columns 3 to 65 have been attributed numbers.

We decided to fix that and to filter out the years that is in our interest and that we have in common with other tables, so the years 2000-2013. We decided to get rid of the Indicator Name and Indicator Code variables as well since the values are the same for every row and they do not provide additional useful information.

Now, we want to filter out the European countries, just like in the first table :

In order to join tables easily, we transformed the columns corresponding to different years to a single “year” column, in order to have at each row of this dataset the GDP of a certain country at a certain year.

To make it easier to manipulate data, we decided to rename our variables for this table as well. We also made sure that the type of our numeric variable (GDP) was numeric and not character, like it was by default. In order to have graphs that are easy to read in the exploratory data analysis, we also decided to divide the avg_gdp column by a billion.

Lastly, we computed the average GDP for each country over the years 2000-2013 in order to be able to plot different variables together.

Table 2: GDP
Country Name Country Code Average GDP
Austria AUT 335.98
Belgium BEL 406.97
Bulgaria BGR 37.41
Croatia HRV 48.12
Cyprus CYP 20.15
Czech Republic CZE 158.48
Denmark DNK 275.37
Estonia EST 16.47
Finland FIN 216.58
France FRA 2283.48
Germany DEU 3003.51
Greece GRC 246.19
Hungary HUN 110.92
Ireland IRL 203.04
Italy ITA 1872.80
Latvia LVA 21.04
Lithuania LTU 30.77
Luxembourg LUX 42.85
Malta MLT 7.27
Netherlands NLD 721.70
Poland POL 365.43
Portugal PRT 200.37
Romania ROU 125.08
Slovak Republic SVK 70.82
Slovenia SVN 39.50
Spain ESP 1176.91
Sweden SWE 425.83
Switzerland CHE 490.18
United Kingdom GBR 2416.76

We now have a dataframe with the following variables :

  • country_name name of the country
  • country_code ISO code of the country
  • avg_gdp the average GDP of a country over the course of 2000-2013

Diabetes

The third dataset, downloaded from https://www.ncdrisc.org/data-downloads-diabetes.html, gives us information about the age-standardised diabetes prevalence for each country and gender from 1980 to 2014.

  • It is composed of 14’000 observations for 7 variables :

    • Country/Region/World Name of the country
    • ISO ISO country code
    • Sex Gender for which the diabetes prevalence is measured in a certain country at a certain year
    • Year Year of observation (1980-2014)
    • Age-standardised diabetes prevalence Diabetes rate considering all ages
    • Lower 95% uncertainty interval Lower confidence interval limit for the diabetes rate
    • Upper 95% uncertainty interval Higher confidence interval limit for the diabetes rate

Like with the first 2 datasets, we filtered our data to keep only European countries and observations between the years 2000 and 2013.

We also decided not to use the 95% confidence interval variable.

Then, we separated our dataset into two subsets. One with data about men.

Another one with data about women.

We then changed the variable names of these 2 subsets to facilitate joining tables later on.

Finally we grouped observations by country to get the mean prevalence/rate of diabetes between 2000 and 2013 for each European country :

  • For men :
Table 3: Diabetes men
Country Code Diabetes rates
AUT 0.053
BEL 0.057
BGR 0.073
CHE 0.050
CYP 0.077
CZE 0.078
DEU 0.059
DNK 0.055
ESP 0.084
EST 0.071
FIN 0.066
FRA 0.071
GBR 0.063
GRC 0.069
HRV 0.071
HUN 0.080
IRL 0.069
ITA 0.065
LTU 0.078
LUX 0.068
LVA 0.071
MLT 0.088
NLD 0.052
POL 0.074
PRT 0.075
ROU 0.062
SVK 0.072
SVN 0.066
SWE 0.058
  • For women :
Table 4: Diabetes women
Country Code Diabetes rates
AUT 0.053
BEL 0.057
BGR 0.073
CHE 0.050
CYP 0.077
CZE 0.078
DEU 0.059
DNK 0.055
ESP 0.084
EST 0.071
FIN 0.066
FRA 0.071
GBR 0.063
GRC 0.069
HRV 0.071
HUN 0.080
IRL 0.069
ITA 0.065
LTU 0.078
LUX 0.068
LVA 0.071
MLT 0.088
NLD 0.052
POL 0.074
PRT 0.075
ROU 0.062
SVK 0.072
SVN 0.066
SWE 0.058

We now have 2 dataframes with the following variables :

  • country_code ISO code of the country
  • prop_men_diabetes or prop_women_diabetesthe average diabetes rate in a country in the 2000-2013 timeframe

Joining tables

For the last step of our tidying, we joined all four tables in one dataset with the country_code key :

Finale Dataset: GDP, diabetes and calories
Country Name Country Code GDP Men Diabetes Women Diabetes Calories from animal protein Calories from plant protein Calories from carbohydrates Calories from fat Total consumption
Austria AUT 335.98 0.053 0.034 245 169 1833 1454 3702
Belgium BEL 406.97 0.057 0.039 238 158 1856 1467 3719
Bulgaria BGR 37.41 0.073 0.064 155 168 1606 846 2775
Croatia HRV 48.12 0.071 0.059 168 148 1691 940 2946
Cyprus CYP 20.15 0.077 0.056 197 127 1291 1019 2633
Czech Republic CZE 158.48 0.078 0.065 218 153 1728 1155 3254
Denmark DNK 275.37 0.055 0.035 273 157 1746 1190 3366
Estonia EST 16.47 0.071 0.064 212 167 1967 842 3188
Finland FIN 216.58 0.066 0.044 269 166 1623 1177 3234
France FRA 2283.48 0.071 0.044 293 161 1611 1480 3545
Germany DEU 3003.51 0.059 0.040 240 159 1785 1276 3460
Greece GRC 246.19 0.069 0.060 250 204 1744 1338 3536
Hungary HUN 110.92 0.080 0.063 193 153 1560 1221 3126
Ireland IRL 203.04 0.069 0.049 279 174 1950 1187 3590
Italy ITA 1872.80 0.065 0.047 241 204 1776 1390 3612
Latvia LVA 21.04 0.071 0.065 203 154 1687 1044 3087
Lithuania LTU 30.77 0.078 0.069 274 198 2055 858 3385
Luxembourg LUX 42.85 0.068 0.039 288 148 1752 1318 3507
Malta MLT 7.27 0.088 0.066 237 204 1932 994 3367
Netherlands NLD 721.70 0.052 0.037 292 136 1599 1195 3222
Poland POL 365.43 0.074 0.066 204 197 1969 1035 3405
Portugal PRT 200.37 0.075 0.052 275 177 1824 1240 3516
Romania ROU 125.08 0.062 0.059 200 220 2003 916 3340
Slovak Republic SVK 70.82 0.072 0.059 140 150 1610 952 2853
Slovenia SVN 39.50 0.066 0.065 230 168 1664 1067 3129
Spain ESP 1176.91 0.084 0.059 279 159 1481 1323 3243
Sweden SWE 425.83 0.058 0.040 285 143 1566 1137 3131
Switzerland CHE 490.18 0.050 0.030 237 138 1660 1392 3426
United Kingdom GBR 2416.76 0.063 0.049 232 178 1748 1256 3414

Missing values

We did not have any NA values in our tables, we think this is due to the fact that we really spent time on gathering quality data that matched in terms of dates and countries.

Exploratory data analysis

First, even though we will be taking the means of the variables with which we are trying to answer our questions, it is interesting to observe their evolution in each country over time. We started with the GDP.

Evolution of GDP per country

We can see that the GDP of France, Germany, Italy, Spain and the United Kingdom had a significant increase between 2000 and 2008.

Plotting GDP against Diabetes (Men & Women)

Now let’s see if there is a relation between the GDP of a country and its diabetes prevalence. (men = blue, women = red)

We observe that apart of 5 outliers, our observations are mostly bunched up at the left of the graph. We decided to exclude these 5 observations, to see if we can observe a trend with the other countries. These outliers, as we can see on the graph before, are the countries that had a big increase of GDP in the time period of 2000-2013.

Without the outliers, we can see a bit more clearly. Indeed, it seems that the richer a country is, the lesser it has a high diabetes rate among its population.

Evolution of the consumption of macronutrients in calories per country

For the second table, we tried to see again if there was a trend in the consumption of different macro-nutrients in the 2000s for each country in our sample.

There do not seem to be any trends in the graphs above and diets seem rather stable in each country, which is why we will take the average consumption for each macro-nutrient. We can however note that the 5 outliers mentioned before tend to have a higher fat consumption than the countries with a smaller GDP.

Plotting GDP against total calories consumed

We then wanted to analyse the relation between a country’s GDP and its individual consumption of each macronutrient as well as its total calorie consumption to see if there’s a trend.(total calories = orange, fat = blue, carbohydrates = purple, animal protein = red, plant protein = green)

We see that the total calorie consumption does not really change. We wanted a close up on the relation between the total calorie consumption with the GDP for each country to see if we can spot outliers again, so we created other plots.

We end up again with these 5 outliers that have a higher than average GDP so if we remove them, we obtain the following plots :

Now we can more easily state that there’s a trend. It appears that the higher a country’s GDP, the higher the total calories consumed, contrary to our hypothesis.

Evolution of Diabetes per country

Once again, we tried to see if the diabetes prevalence in each country changed over the years 2000-2013.

We saw right away that the prevalence of diabetes is higher for man than women across all countries (there are however two exceptions : in Romania between 2000 and 2003 and Slovenia between 2000 and 2006).

We observed three different scenarios for countries that we selected: A decrease over time of diabetes over time for:

  • Belgium
  • Denmark
  • Finland

A decrease over time for women but not for men for :

  • Austria
  • Malta
  • Netherlands
  • Germany
  • Italy
  • Spain
  • Switzerland

In other European countries, the prevalence of diabetes is increasing (at different paces) over time.

Plotting Diabetes against each type of macronutrient consumption

Finally, we want to plot the relation between the diabetes prevalence against the total calorie consumption as well as each type of macronutrient consumed.

We can see a negative trend for the total consumption, the calories from animal protein and the calories from fat. We can observe a positive trend against calories from plant protein. For protein from carbohydrates, we can see a slighty positive trend for women.

Plotting Diabetes against each type of macronutrient consumption (without outliers)

Now, since they affected our plots that included the GDP variable so much, we want to see if we have different trends when we remove our 5 outliers.

Without our 5 outliers, we observe not much change in the trend of each type of calories consumed apart for carbohydrates where the trend changes for men and become slightly positive.

Analysis

Our research questions

1.Do European countries that have higher GDPs really have lower diabetes prevalence ?

2.Do European countries that have higher GDPs consume less calories ?

3.How do the macronutrients (animal protein/plant protein/fat/carbohydrates) consumed differ between richer and poorer governments ? And how do these differences relate to the diabetes prevalence in these countries ?

4.What is the typical diet that can be observed in richer states that relates to lower diabetes prevalence ?

Conclusion